Hoist mechanism.



Cl F. BLEDSOE.

HOIST MECHANISM.

APPLICATION FILED MAY 18. 19l6.

Patented June 26, 1917.

3 $HEETSSHEET l- I fnvenz m" CELTZ I ,ZZed'poe 1: w i 33, Jf

m: NORRII Pain: 00.. rnamuma. wasumamn, n, c,

pairs s n PATEN anon.

CARL F. BLEDSOE, OF CHICAGO, ILLINOIS, ASSIGNOR TO OGLE CONSTRUCTION COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

I'IOIST MECHANISM.

Specification of Letters Patent.

Application filed May 18, 1916. Serial No. 98,272.

To all whom it may concern:

Be it known that I, CARL F. BLEnsoE, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Hoist Mechanism, of which the following is a specification.

My invention relates to improvements in automatic locking devices for hoisting mechanisms and the like'and has for one object to provide a new and improved type of automatic lock which will always be ready for instant operation but which will never go into operation unless the driving member is released from the driving mechanism and commencesamovement under influences independent of the driving mechanism.

My invention, that is to say, when applied for instance to a hoisting drum, provides means whereby at all positions of the hoisting drum it will drive freely and easily, but will instantly be held against rotation whenever the load carried by the hoisting drum tends to rotate the drum in dependent of the drive mechanism. Other objects of my invention will appear from time to time in the specification.

The'invention is illustrated more or less diagrammatically in the accompanying drawings, wherein- Figure l is a plan view of a hoisting mechanism showing my device in use;

Fig. 2 is a side elevation, and

Fig. 3 is a section along the line 33 of Fig.

Like parts are indicated by like letters in all the drawings.

I have shown my invention as applied to a hoisting drum, but it is of course evident that it might be applied to any suitable mechanism, and in view of the fact that the hoisting drum is not a part of my invention, I have shown it more or less diagrammatically.

A, A are the side frames of the hoist. A is the drive shaft driven from any suitable source of power not here shown and rotatably mounted in the bearings A A The two clutch members A A are shown on the shaft controlled by the lever A. Driven respectively from these clutch members are gears or pinions A A". The pinion A is in mesh with the gear A on the counter shaft A and at the opposite end said shaft has keyed to it the pinion A in mesh with the gear A The pinion A is in mesh with the gear A on a jack shaft A and this jack shaft A carries a pinion 13* in mesh with the gear B so that when one clutch is in the operative position, the main counter shaft A is driven in one direction, when the other clutch is in the operative position, it is driven in the reverse direction.

B is a hoisting drum keyed to the shaft B which shaft is mounted in bearings B Keyed to the shaft is a gear B in mesh with a pinion B on the counter shaft A so that rotation of the counter shaft in one direction or the other causes the drum to rotate in one direction or another as the case may be. i

C is a reversing and controlling lever adapted to be operated upon by cam members C C on a sleeve C shifted by means of a screw G which screw is driven through a sprocket C chain C and sprocket C from the drum shaft. The lever C cooperates with a cam C, control shaft C worm wheel C and worm C to assist in the automatic control of the hoist. These parts form no chief part of my invention and therefore I have not shown them with any great degree of minuteness. However, they are suflicient to show that in the preferred form the hoisting drum is driven by a driving source of power which is turned on and off or connected and disconnected automatically so as to cause the drum first to rotate in one direction and. then in. another. The lever, of course, is for the additional manipulation by the hand of the operator.

It sometimes happens that the operator is unskilful or that something goes wrong, and then the load which is being raised by the drum starts down. The operator throws the clutches into position and the load is suddenly arrested and something is broken. It is to obviate this danger that my auto matic stop mechanism is provided. This automatic stop mechanism I will now describe. Keyed on the shaft A is a. mitered gear D. This mitered gear D is in mesh with a gear D on a worm shaft D This worm shaft is mounted in bearings D on the frame, and carries a worm D rigidly mounted thereon. This worm is in mesh with a worm wheel D on the main drum shaft B the worm wheel. being keyed to that shaft so as to always rotate with it in unison with the drum.

Because the jack-shaft A is always in driving connection through the gear and pinion with the drum, it is obvious that it always rotates when the drum rotates in a forward direction. lVhen the drum rotates in the forward direction, the jack-shaft rotates in the forward direction. If the drum reverses, the jack-shaft reverses so that the worm always turns in consonance with the worm wheel.

The arrangement of the parts is such that there is sufficient backlash provided so that when the driving mechanism is driving the drum in one direction, the worm is always following the worm wheel, but is a little in advance of it so that there is no driving done by the worm and the worm wheel. The same rule prevails when the mechanism is going in the opposite direction, thus the worm always moves along with the worm wheel without ever coming in contact with it, thus no power is lost by the engagement of the worm and the worm wheel.

It will be noted that the relative pitch of the worm and worm wheel is such that if the worm is not driven and if the wheel is driven, the face of the wheel will come in contact with the worm and be locked because the inclination of the worm is not sufficiently great to permit the wheel-to drive it, thus at all positions of the mechanism, the worm is always in mesh with the worm wheel but never in contact with it unless there is a tendency for the worm wheel to rotate being driven by the rotation of the drum, and the automatic stop is always ready for in .stant operation when it is needed.

I claim:

1. The combination with a driven member and driving means therefor, of a worm wheel. mounted for rotation with the driven member, and a worm in mesh with the worm wheel .and driven by the driving means, the driving connection between the driving means and the driven member being altogether separate from the worm.

2. The combination with a driven member and driving. means therefor, of a worm wheel mounted for rotation with the driven member, and a worm in mesh with the worm wheel and driven by the driving means, the driving connection between the driving means and the driven member being altogether separate from the worm, the pitch ofthe worm and wheel being such that a rotation of the wheel will not result in a rotation of the worm.

3. The combination with a driven memher and a driving means therefor, and a driving connection between them, of a worm wheel mounted on the driven member for rotation, a worm in mesh with the worm wheel. and means responsive to the operation of the driving connection for rotating the worm in unison with. said driving connection.

4-. The combination with a driven mem 7 ber, a driving member therefor, and a connection between them, of means operating partially in response to the movement of the driven member and partially in response to the movement of the driving member; for locking the driven member against movementwhen it is disconnected from the driving member.

6. The combination with a driven member, a driving member therefor, and a connection between them, of an automatic locking device adapted to be out of contact with the driven member when the driven member is being positively driven but to be in contact with a portion of the driven member when it is being driven independent of the driving member.

7 The combination with a driven member, a driving member therefor, and a connection between them, of a worm wheel mounted for rotation with the driven member, a worm in mesh with the worm wheel, and means responsive to the operation of the driving member for driving the worm in unison with the movement of the worm wheel, with the worm and wheel out of con tact one with another.

8. The combination with a driven mem ber, a driving member therefor, and a' connection between them, of a worm wheel mounted for rotation with the driven member, a worm in mesh with the worm wheel, means responsive to the operation of the driving member for driving the worm in unison with the movement of the worm wheel, with the worm and wheel out of Com tact one with another, and a driving connection between the driven member and the worm comprising a portion of the driving and driven members, there being sufficient back-lash in such connection to permit the worm wheel to come into operative stopping engagement with the worm when the driven member rotates independent of the driving member before the worm itself is rotated.

9. The combination with a driven member and driving means therefor, of means for connecting and disconnecting the driving and driven members, an automatic floating stop in permanent operative relation In testimony whereof, I aifix my signa- With respect to the driven member and means ture in the presence of tWo Witnesses this for driving it synchronously With the driv- 10th day of May, 1916.

ing of the driven member, said stop being CARL F. BLEDSOE. adapted to instantly go into operation when WVitnesses:

the driven member commences rotation in- ESTHER VAN FRANK,

dependent of the driving means. CHRISTINA DEANS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

